1. Field of the Invention
This invention relates to a process for improving the adhesion of finishes on oiled and/or hydrophobicized leathers and to the use of aqueous dispersions as a primer for improving the adhesion of finishes on oiled and/or hydrophobicized leathers.
2. Statement of Related Art
A leather finish is the protective layer applied to the leather dried after tanning in oiling to protect it against moisture, soiling and damage. An optimal finish is required inter alia to adhere firmly to the leather. Unfortunately, most finishes do not satisfactorily fulfill this requirement. Thus, polyurethane-based finishes for example give good fastness values and flexibilities so that the finish film is virtually impossible to break; unfortunately, adhesion problems frequently arise with finishes of this type (cf. "Das Leder" 25, 167-171 (1974)). In the case of hydrophobicized leathers, there is the further difficulty that any improvement in adhesion is often accompanied by a deterioration in the hydrophobicization.
The weakly crosslinking aqueous polyurethane dispersions leather finishes also fail to satisfactorily meet the demands made of them.